A high-voltage power supply that outputs high voltages having a predetermined polarity and a reverse polarity performs control in a manner that, during a transition period in which switching of a target voltage of the high voltage having the reverse polarity from the predetermined polarity is performed, a setting value in accordance with a voltage higher than a target voltage is set as the voltage having the reverse polarity, and then a setting value in accordance with the target voltage is set as the voltage having the reverse polarity.